Hartmann J F, Hutchison C F
Proc Natl Acad Sci U S A. 1981 Mar;78(3):1690-4. doi: 10.1073/pnas.78.3.1690.
The penetration of the zona-pellucida by hamster sperm in vitro (assay drops) was inhibited by aliquots of ultrafiltrates obtained from another set of drops (experimental drops) in which capacitated sperm had interacted with the surface of the zona pellucida. This inhibition was inversely related to the concentration of sperm in the assay drop, and it was noted that the inhibitory response declined when the gametes in the assay drop were incubated together beyond the standard 90-min period. Thus, inhibition was not irreversible. A number of criteria suggest that the inhibitory activity resides in at least some of the peptides (S1 factors) released at four different times after contact between the surfaces of the sperm and zona pellucida. Like the S1 factors, the substances responsible for the inhibitory activity of the supernatants, collected at 2 and 50 min after gamete combination, traversed ultrafilters with Mr cutoffs of 5000 and 2000, respectively, and were inactivated by subtilisin. In addition, the quantity of inhibitory material recovered in the ultrafiltrates from experimental drops containing various numbers of eggs was well correlated with the amount of 2- and 50-min S1 factors from similar experimental drops. These results suggest that the S1 factors are peptide modulators of the penetration process and it is speculated that one of their functions may be to prevent or at least to discourage polyspermic penetration of the hamster zona pellucida.
仓鼠精子在体外（试验液滴）穿透透明带的过程，受到从另一组液滴（实验液滴）获得的超滤物等分试样的抑制，在该组液滴中，获能精子已与透明带表面相互作用。这种抑制作用与试验液滴中精子的浓度呈负相关，并且注意到当试验液滴中的配子一起孵育超过标准的90分钟时，抑制反应会下降。因此，抑制作用不是不可逆的。一些标准表明，抑制活性存在于精子与透明带表面接触后四个不同时间释放的至少一些肽（S1因子）中。与S1因子一样，配子结合后2分钟和50分钟收集的上清液中负责抑制活性的物质，分别能通过截留分子量为5000和2000的超滤膜，并且会被枯草杆菌蛋白酶灭活。此外，从含有不同数量卵子的实验液滴的超滤物中回收的抑制物质的量，与来自类似实验液滴的2分钟和50分钟S1因子的量密切相关。这些结果表明，S1因子是穿透过程的肽调节剂，据推测它们的功能之一可能是防止或至少阻止仓鼠透明带的多精受精。
